JP2010140848A - Manufacturing method of organic light emitting device - Google Patents

Abstract

The present invention relates to a sealing method that maintains a light heating temperature in a frit material layer having a thickness such that the electrode layer of the substrate does not peel off, melts the entire frit material layer, has good substrate adhesion, and does not generate cracks. A method of manufacturing an organic light emitting device is provided.
A method of forming frit material layers 5 and 6 on a sealing substrate 9 and melting the frit material layers 5 and 6 by irradiating a laser beam to seal the element substrate 1 and the sealing substrate 9 together. A step of forming the frit material layers 5 and 6, wherein the step of forming the frit material layers 5 and 6 irradiates the plurality of frit material layers 5 and 6 containing a laser light absorber with laser light transmission. A method of manufacturing an organic light emitting device in which laser light is irradiated from the frit material layer 6 side having a high laser light transmittance.
[Selection] Figure 1

Description

  The present invention relates to a method for manufacturing an organic light-emitting device that uses light emitted from an organic electroluminescence (hereinafter sometimes referred to as “organic EL”) element for a light source, a display, and the like.

  One of the flat display panels is an organic EL display on which an organic light emitting element is mounted, and research and development are actively carried out. Since this organic light emitting device has a property that is weak against moisture and oxygen, it is necessary to protect it from moisture and oxygen.

  As a technique for protecting the organic light emitting element from moisture, oxygen, and the like, there is a hollow sealing method. In this method, a space is interposed between the element substrate on which the organic light emitting element is formed and the sealing substrate, and an inert gas is sealed, and the element substrate and the sealing substrate are bonded with a sealing material such as a frit material. This is a technique for sealing an organic light emitting element by sealing.

  As an example of the method, as disclosed in Patent Documents 1 and 2, a method of melting and sealing a frit material layer by laser irradiation is known.

JP 2007-115692 A Japanese Patent Laid-Open No. 2007-200836

  Here, in the hollow sealing method, it is necessary to widen the space between the element substrate and the sealing substrate. This is because if the space between the element substrate and the sealing substrate is narrow, the electrode layer of the element substrate peels from the bending due to the pressing of the sealing substrate.

  However, for example, when a laser is irradiated to a frit material layer having a thickness of 100 μm, the thermal energy attenuates as the distance from the laser irradiation position increases, and heat is not transferred to a distant contact portion (contact portion between the substrate and the frit material layer). In some cases, it was impossible to seal properly.

  Patent Document 2 discloses that a transparent material layer and an opaque material layer are laminated to adjust the thickness of the sealing material. However, the method of Patent Document 2 has a problem that light is absorbed only by the opaque material layer, and cracks are likely to occur in the substrate due to local light heating, so that the desired sealing cannot be performed. In addition, a temperature difference occurs between the transparent material layer that does not include the light absorbing material and the opaque material layer that includes the light absorbing material, and distortion occurs after laser irradiation, and peeling occurs at the layer interface between the transparent material layer and the opaque material layer. The problem of being generated.

  Therefore, the present invention maintains the light heating temperature in the frit material layer having such a thickness that the electrode layer of the element substrate does not peel off, melts the entire frit material layer, has good substrate adhesion, and generates cracks. Aims to give no sealing.

  In order to solve the above problems, the present invention includes a step of forming a frit material layer on an element substrate provided with an organic light-emitting element having an organic compound layer sandwiched between a pair of electrodes, or a sealing substrate, and a laser. A step of melting the frit material layer by irradiating light and sealing the element substrate and the sealing substrate, wherein the frit material layer is formed. Is a step of laminating a plurality of frit material layers containing a laser light absorber so that the laser light transmittance sequentially increases or decreases, and the laser light is transmitted to the frit material layer side having a high laser light transmittance. The manufacturing method of the organic light-emitting device characterized by irradiating from is provided.

  According to the present invention, the light heating temperature in the frit material layer having such a thickness that the electrode layer of the element substrate is not peeled is maintained, the entire frit material layer is melted, and the substrate adheres well and cracks are generated. There can be no sealing.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view showing an example of an organic light-emitting device manufactured according to the present invention. In the organic light-emitting device 10 of FIG. 1, one or more organic light-emitting elements having an organic compound layer 3 sandwiched between a pair of electrodes composed of a first electrode layer 2 and a second electrode layer 4 are provided on an element substrate 1. . In this organic light emitting device, by applying a voltage between the first electrode layer 2 and the second electrode layer 4, holes injected from one electrode and electrons injected from the other electrode are formed. Light is emitted by recombination in the light emitting layer in the organic compound layer 3.

  In the present invention, the element substrate 1 and the sealing substrate 9 are sealed by the frit material layers 5 and 6. The frit material layers 5 and 6 are formed so as to cover the outside of the display region, and can block moisture, oxygen, and the like from the outside air.

  Next, components of the organic light emitting device in the present invention will be described.

  As the element substrate 1, a glass substrate, a Si substrate, or the like can be used.

  As a constituent material of the first electrode layer 2 and the second electrode layer 4, a known electrode material can be used. Specifically, a metal conductive film such as Al or Ag, a transparent conductive film such as ITO or IZO, and a laminated film thereof can be used.

  As the constituent material of the organic compound layer 3, known charge transport materials (hole injection / transport materials, electron injection / transport materials) and light-emitting materials can be used.

  As hole injection / transport materials, triarylamine derivatives, phenylenediamine derivatives, triazole derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives, pyrazolone derivatives, oxazole derivatives, imidazole derivatives, pyrazoline derivatives, pyrazolone derivatives, oxazole derivatives, fluorenone derivatives , Hydrazone derivatives, stilbene derivatives, phthalocyanine derivatives, porphyrin derivatives and poly (vinyl carbazole), poly (silylene), poly (thiophene), and other conductive polymers can be used.

  As electron injection / transport materials, oxadiazole derivatives, oxazole derivatives, thiazole derivatives, thiadiazole derivatives, pyrazine derivatives, triazole derivatives, triazine derivatives, perylene derivatives, quinoline derivatives, quinoxaline derivatives, fluorenone derivatives, anthrone derivatives, phenanthroline derivatives, organometallics Complexes and the like can be used.

  As the light emitting material, a fluorescent material or a phosphorescent material can be used. For example, an aluminum quinolinol complex, a beryllium quinolinol complex, hydroxyphenyl oxazole, hydroxyphenyl thiazole, an azomethine metal complex, or the like can be used.

  In addition, the organic compound layer 3 may be comprised with the single layer of only a light emitting layer, and may be comprised with the several layer including the light emitting layer.

  The frit material layers 5 and 6 are preferably made of a fine particle paste.

  Fine particles are magnesium oxide, calcium oxide, barium oxide, lithium oxide, sodium oxide, potassium oxide, boron oxide, zinc oxide, tellurium oxide, aluminum oxide, silicon dioxide, titanium oxide, tin oxide, phosphorus oxide, ruthenium oxide, oxide It consists of iron, copper oxide, tungsten oxide, borosilicate glass, etc.

  Moreover, a cellulose type is used as a binder, and ethyl cellulose, butyl cellulose, etc. are mentioned.

  Moreover, the frit material layers 5 and 6 contain a laser light absorber. Specifically, iron, manganese, copper, vanadium, and carbon black are used as the laser light absorber.

  As the sealing substrate 9, any material can be used as long as it is a highly transparent material with little laser light absorption, such as a glass substrate.

  Next, the production method of the present invention will be specifically described.

  An organic light emitting element is formed on the element substrate 1, and a known manufacturing method can be used as the forming method.

  On the other hand, the frit material layers 5 and 6 are formed on the sealing substrate 9 along the outer periphery of the display region. In this example, a plurality of frit material layers 5 and 6 are laminated so that the laser light transmittance decreases sequentially. That is, the laser light transmittance of the frit material layer 6 is larger than the laser light transmittance of the frit material layer 5. Furthermore, it is preferable that the laser light transmittance of the frit material layers 5 and 6 is smaller than the laser light transmittance of the sealing substrate 9 which is the substrate on the laser light irradiation side.

  The laser beam transmittance of the frit material layers 5 and 6 can be adjusted by changing the content of the laser beam absorber. When the content of the laser light absorber is increased, the laser light absorption rate is increased and the laser light transmittance is decreased. On the other hand, when the content of the laser light absorber is decreased, the laser light absorption rate is decreased and the laser light transmittance is increased.

  The content of the laser light absorber is not particularly limited, but the content of the laser light absorber in the frit material layer 6 is 10 to 20% by weight, and the transmittance of the laser light having a wavelength of 800 to 1100 nm is adjusted to 50 to 60%. The content of the laser light absorber in the frit material layer 5 is preferably 30 to 40% by weight, and the transmittance of laser light having a wavelength of 800 to 1100 nm is preferably adjusted to 0 to 10%. In addition, as shown in FIG. 2, when the three-layer structure of the frit material layers 5, 6, and 8 is used, the content of the laser light absorber in the frit material layer 8 is 2 to 5 wt%, and the wavelength is 800 to It is preferable to adjust the transmittance of 1100 nm laser light to 70 to 80%.

  The frit material layers 5 and 6 can be formed by a known method such as a coating method, a dispenser method, or a screen printing method. When a frit material paste is used, the frit material layers 5 and 6 are formed and then dried and fired to decompose and remove organic substances such as a binder.

  The total thickness of the frit material layers 5 and 6 is preferably 60 μm to 200 μm. If the thickness is less than 60 μm, the second electrode layer 4 on the facing surface may be peeled off due to the bending due to the pressing of the sealing substrate 9. On the other hand, if it is thicker than 200 μm, there is a possibility that the desired product is made thinner. When the thickness is larger than 100 μm, a three-layer structure of frit material layers 5, 6 and 8 is preferable as shown in FIG.

  The frit material layers 5 and 6 may be formed on the element substrate 1 or may be laminated so that the laser light transmittance increases sequentially.

  Next, the organic light emitting element formation surface of the element substrate 1 and the sealing substrate 9 are disposed to face each other.

  Thereafter, while applying a load, the laser is irradiated from the frit material layer side having a high laser light transmittance, that is, the sealing substrate 9 side which is the frit material layer 6 side, and the entire frit material layers 5 and 6 are melted. The element substrate 1 and the sealing substrate 9 are sealed. The laser power output is preferably 15 to 60 W, and the laser wavelength is preferably 800 to 1100 nm.

  First, the frit material used in this example was prepared by adjusting the transmittance at a laser beam wavelength of 1064 nm to a paste of fine particles of low-melting glass containing a laser beam absorber shown in the following table. As a method of measuring the transmittance at a laser beam wavelength of 1064 nm, each adjusted frit material was previously formed on a glass substrate and measured with a spectrophotometer.

<Example 1>
The organic light emitting device 10 shown in FIG. 1 was produced by the following method.

  On the element substrate 1, an organic light-emitting element composed of the first electrode layer 2, the organic compound layer 3, and the second electrode layer 4 was formed.

Specifically, first, a laminated film of an Al film and an ITO film was formed on a glass substrate as the element substrate 1 by a sputtering method to form the first electrode layer 2. At this time, the film thickness of the first electrode layer 2 was 200 nm for the Al film and 20 nm for the ITO film. Next, a hole transport layer α-NPD 30 nm, a light emitting layer Balq 50 nm, an electron transport layer Bphen (vasophenanthroline) 10 nm, and an electron injection layer Bphen + CsCO ₃ 60 nm are sequentially formed on the first electrode layer 2 by vacuum deposition. Compound layer 3 was formed. At this time, the film thickness of the organic compound layer 3 was 150 nm. Next, an ITO film was formed on the organic compound layer 3 by sputtering to form a second electrode layer 4. At this time, the film thickness of the second electrode layer 4 was 30 nm.

  On the other hand, the paste of the frit material 3 was applied to a glass substrate (laser light transmittance of 95% at a wavelength of 1064 nm) as the sealing substrate 9 with a dispenser so as to have a width of 1 mm and a thickness of 50 μm. On top of that, the paste of the frit material 4 was applied with a dispenser so as to have a width of 1 mm and a thickness of 50 μm, and the frit material layers 5 and 6 were laminated. Thereafter, the frit material layers 5 and 6 were dried at 120 ° C. and fired at 300 ° C.

  Next, the sealing substrate 9 and the element substrate 1 are bonded together, and the frit material layers 5 and 6 are irradiated with laser from the sealing substrate 9 side while applying a load of 98.07 N (10 kgf), so that the frit material layer 5 And the whole of 6 was melted. The laser power output at that time is 25 W and the laser wavelength is 1064 nm.

  The light heating temperature was maintained at 400 ° C. in order from the frit material layer 6 close to the laser irradiation position to the contact portion between the frit material layer 5 and the element substrate 1, and the element substrate 1 and the sealing substrate 9 were sealed. Even when twisted, it was confirmed that no peeling occurred between the frit material layers 5 and 6, and no crack was generated in the element substrate 1 by an optical microscope.

<Example 2>
After applying the paste of the frit material 2 on the sealing substrate 9 with a dispenser so as to have a width of 1 mm and a thickness of 100 μm, the paste of the frit material 3 is applied thereon so as to have a width of 1 mm and a thickness of 50 μm. It was applied with a dispenser. Thereafter, the paste of the frit material 4 was applied thereon with a dispenser so as to have a width of 1 mm and a thickness of 50 μm, and the frit material layers 5, 6 and 8 were laminated. Thereafter, the frit material layers 5, 6 and 8 were dried at 120 ° C. and fired at 300 ° C.

  An organic light emitting device 11 shown in FIG. 2 was produced in the same manner as in Example 1 except that this sealing substrate was used.

  The light heating temperature is maintained at 400 ° C. in order from the frit material layer 8 close to the laser irradiation position to the contact portion between the frit material layer 5 and the element substrate 1 through the frit material layer 6, and the element substrate 1 and the sealing substrate 9 are sealed. Weared. Even when twisted, it was confirmed that no peeling occurred between the frit material layers 5, 6, and 8, and no crack was generated in the element substrate 1 by an optical microscope.

<Comparative Example 1>
An organic light emitting device was manufactured in the same manner as in Example 1 except that the frit material layer 6 was formed with the frit material 4 and the frit material layer 5 was formed with the frit material 3.

  Heat loss occurred due to heat absorption of the frit material layer 6 close to the laser irradiation position, and light heating to the contact portion between the frit material layer 5 and the element substrate 1 was insufficient. Although it was confirmed by an optical microscope that the element substrate 1 was not cracked, it was easily peeled off by twisting, and the element substrate 1 and the frit material layer 5 were not sufficiently sealed.

<Comparative example 2>
An organic light emitting device was manufactured in the same manner as in Example 1 except that the frit material layer 6 was formed of the frit material 1.

  Heat absorption concentrated on the frit material layer 5 through the frit material layer 6 close to the laser irradiation position, and cracks occurred in the element substrate 1 in contact with the frit material layer 5.

It is a schematic sectional drawing which shows an example of the organic light-emitting device manufactured by this invention. It is a schematic sectional drawing which shows the other example of the organic light-emitting device manufactured by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Element substrate 2 1st electrode layer 3 Organic compound layer 4 2nd electrode layer 5, 6, 8 Frit material layer 9 Sealing substrate

Claims (3)

  A step of forming a frit material layer on an element substrate provided with an organic light emitting element with an organic compound layer sandwiched between a pair of electrodes or a sealing substrate, and melting the frit material layer by irradiating laser light And a step of sealing the element substrate and the sealing substrate, wherein the step of forming the frit material layer sequentially increases or decreases the laser light transmittance. As described above, the step of laminating a plurality of frit material layers containing a laser light absorber, wherein the laser light is irradiated from the frit material layer side having a high laser light transmittance. Production method.   2. The method of manufacturing an organic light emitting device according to claim 1, wherein a laser light transmittance of the frit material layer is lower than a laser light transmittance of a substrate on which the laser light is irradiated.   3. The step of forming the frit material layer is a step of laminating a plurality of frit material layers on the sealing substrate so that the laser light transmittance is sequentially reduced. The manufacturing method of the organic light-emitting device of description.

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